Vincenzo Nibali (Astana) recognised that he took a step forward towards sealing his second Grand Tour of the 2013 season after he strengthened his overall lead over all his rivals on the first Pyrenean stage, where thanks to the very rough weather conditions, he took more of an advantage than expected.

Nibali had said on Saturday that he was ok in poor weather and that, as anybody could have seen at the Tre Cime de Lavaredo victory at the Giro d'Italia, won in a snowstorm, was an understatement. In fact whilst Nibali seems able to maintain his strength as the temperatures plummet, others have far more difficulty in doing so: and that was arguably what made the biggest difference on Saturday.

Prior to Saturday's hellish stage, overall there were three riders at less than a minute on Nibali. Now there is only one - American Chris Horner (RadioShack Leopard) - and even he was squeezed back by four seconds, to 50 seconds, as Nibali shed Horner on the last corner of the Collado de la Gallina.

Ever cautious, Nibali refused to say he has won the race - and with Sunday's monster Pyrenean stage and the Angliru yet to come, that is logical. But the time differences are growing steadily and on Saturday Nibali both saw Nicolas Roche (Saxo-Tinkoff) drop from a close second to a distant sixth and two of his top rivals, Alejandro Valverde (Movistar) and Joaquim Rodriguez(Katusha), lose more time.

"It was a very hard stage with the temperatures dropping so much, and everybody really suffered on the descent of the Envalira," Nibali said. "Little by little, people are getting weeded out."

Is he closer to the win, now? "It's very hard, but today was a big step forward. Horner is at 50 seconds, though, and he's really strong."

With Valverde and Rodriguez losing time, Nibali said he had no reason to go on the attack. "We had already done a lot of damage and there are a great many stages to go. Valverde paid a bit of a price with the weather and I'm sorry about Ivan Basso (Cannondale) and his having to abandon.

"Purito [Rodriguez] did a lot of attacking and tried to mix things up, but even he suffered in the cold, too."

Nibali said he was optimistic, but described the race as "still very open, anything can happen. Cold and climbs combined make for a hard race, and there's still a long way to go."